Process for the preparation of alloys



Dec. 29, 1959 E. s. NOSSEN ETAL 2,919,189

PROCESS FOR THE PREPARATION OF ALLOYS Filed March '7, 1958 7! 7777mmPecans-esp R 2 o I I I l I I I I INVENTORS 'mvssrin/osssm Port. Pee/(s"PROCESS FOR THEPREPARATION F ALLOYS Ernest Samuel Nossen and Roy E.Parks, Passaic County,

N.J., assignors to Alscope Explorations, Ltd, Vancouver, BritishColumbia, Canada, a corporation of Canada Application March 7, 1958,Serial No. 712,903 20 Claims. (Cl. 75-135) This application is acontinuation-in-part application of our co-pending application SerialNo. 573,614,1filed on March 26, 1956, now abandoned.

This invention relates to metal alloys and more particularly to aprocess for the preparation of alloys of refractory metals. For thepurpose of this, specification and the appended claims the termrefractory metals is deemed to mean metals such as, for example,titanium, zirconium, molybdenum, chromium, manganese, vanadium etc., theoxides of which are not readily reduced by carbon by conventionalmethods.

Alloys containing relatively small percentages of re fractory metalshave recently gained increased technical importance. It has, forexample, been found that as little as 0.5% of titanium confer uponcertain aluminum alloys an increase in strength of as much as 30%, thatrelatively small amounts of Ti improve the corrosion resistance ofmagnesium alloys, refine thev grain of steel, retard'age hardening inaluminum alloys etc.

The preparation of these alloys, however, is fraught with considerabledifiiculties. These difficulties are due I to the fact that the meltingpoint of refractory metals such as titanium, zirconium, molybdenum andthe like, is relatively high, and generally considerably above themelting point of most metals or alloys, the properties of which are tobe influenced by additions of such refractory metals. In fact, themelting point of most refractory metals is above 1700 C.

In the customary methods for the production of alloys containingrefractory metals, the other metal constituents have to be melted andheated to a temperature which is close to the melting point of therefractory metal or metals. When titanium, for example, is to be alloyedwith major amounts of such metals as aluminum, magnesium, iron,manganese, or copper, which have melting points considerably below thatof titanium, itis very undesirable to heat the major constituent orconstituents almost to the melting point of titanium. Such overheatingsubstantially beyond the melting point of the major constituent resultsin appreciable losses of metal due to evaporation and oxidation.Moreover, a considerable amount of heat energy is lost.

' The metallic forms of titanium, zirconium etc. are relativelyexpensive, and the preparation of an alloy prepared from even a smallpercentage of refractory metal is thusvery costly. The use of very hightemperatures in the preparation of the alloys, furthermore, calls formelting pots or crucibles extremely resistant to heat which pots orcrucibles are expensive and difi'icult to manufacture.

It is, therefore, an object of the present invention to provide aprocess for the preparation of alloys comp-rising refractory metalstogether with major amounts of nonrefractory metals which may be carriedout at temperatures considerably below the melting point of therefractory. metals to be incorporatedin the alloy.

Another object of the invention is the provision of such Patented Dec.29, 1959 a process in which the losses of metallic constituents are heldto a minimum.

A further object of the invention is the provision of a process for thepreparation of alloys comp-rising re: fractory metals, wherein saidrefractory metals are supplied to the process in the form of relativelyinexpensive and readily available starting materials.

Still another object of the invention is the provision of such processwhich may be carried out in a simple manner and without requiringexpensive apparatus while resulting in alloys of excellent quality athigh yields.

Furthermore, it is an object of the invention to provide a process forthe preparation of alloys comp-rising refractory metals which lendsitself to continuous operation and to the reclamation and reuse ofauxiliary materials and by-products.

It isstill a further object of this invention to improve generally onprocesses for the preparation of refractory metal alloys as nowcustomarily practiced.

" Other objects and many of the attendant advantages of the presentinvention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description and to thespecific examples of embodiments of the process of the invention.

i In its more specific aspects, the present invention contemplates thepreparation of alloys comprising refractory metals by reacting one orseveral oxides of refractory metals with an equivalent amount ofreducing metal in the presence of an amount of non-reacting metal and ofamolten salt solvent as hereinafter defined.

A reducing metal for the purposes of the process of the invention is ametal having a lower position in the electromotive series at therelevant reaction temperature and under the relevant reaction conditionsthan the refractory metal of the oxide or oxides to be reduced.Generally, such reducing metals may also be defined in terms of the freeenergy of formation of their oxides per atom oxygen at the reactiontemperature, the energy of formation of the oxide of the reducing metalbeing generally higher than that of the refractory metal oxide or oxideswhich it is desired to reduce. It has been found, however, that metalsthe oxides of which have a free energy of formation equal to or evenslightly greater than that of the reducing metal may be successfullyprepared in good yields by the process of the invention.

According to the process of the invention, additional metal oxides otherthan those of refractory metals may be reduced simultaneously by thereducing metal. .Iron oxide (Fe O may be mentioned as an example of suchadditional non-refractory metal oxide. v

The non-reacting metal in the presence of which the reaction between therefractory metal oxide or oxides and the reducing metal is carried outmay either constitute an excess or the reducing metal or it may consistof another metal or metals capable of alloying with the refractory metalor metals. This non-reacting metal, which thus will be a constituent ofthe alloy to be obtained, acts as a diluent and moderates the rate ofthe reaction between the reducing metal and the oxide or oxides.

The molten salt solvent to be employed in the inventive process is asalt or a mixture of salts having a melting point below the temperatureat which the reaction between the oxide or oxides of the refractorymetals (hereinafter referred to as primary oxide) and the reducing metalis performed, which salt or mixture of salts is capable of dissolvingthe oxide of the reducing metal formed by the reaction and hereinafterreferred to as secondary oxide. Since the preferred reducing metals forthe inventive process are aluminum and/or magnesium, the molten saltsolvent should consequently be capable of dissolving aluminum oxide andmagnesium oxide. It has been ascertained that the readily availablefluorides and chlorides of the metals of the first through the thirdgroups of the Periodic System, such as for example Ca-, Na-, AI- andK-chlorides and fluorides having a boiling point above 700 C. areparticularly suitable for the intended purpose. S j

The process of the invention thus comprises essentially reacting atleast one primary oxide of a refractory metal with an equivalent amountof reducing metal in the presence of an amount of non-reacting metal ata temperature above the melting point of the reducing metal and thenon-reacting metal, but below the melting point of the refractory metalor metals, and dissolving the secondary oxide formed by the reaction inthe molten salt solvent.

It has been established by us that the removal of the secondary oxide ofthe reducing metal or slag has an important bearing on the process ofpreparing alloys of refractory metals from their primary oxides byreaction with reducing metals in the presence of non-reacting metals.

It has formerly been proposed to reduce oxides of refractory and othermetals by aluminum in a continuous operation by adding small batches ofprimary oxide at frequent intervals to a molten bath of the reducingmetal while keeping the metal bath at the proper reaction temperature bymeans of an electric are or by another heating device.

We have now ascertained that this procedure is practical onlyin veryshort runs and becomes virtually inoperative as soon as the surface ofthe molten metal is completely covered by a slag of secondary aluminumoxide formed by the reaction of the aluminum with the primary metaloxide. Aluminum oxide or alumina has a melting point above 2000 C. Assoon as a cover of tough impermeable slag or solid alumina forms on themelt, no further reaction takes place.

A continuous operation at much lower temperature than heretoforeproposed is possible by the process of our invention wherein the moltensalt solvent is used for continuously removing the secondary oxide. Whenthe metallic melt to which the oxide or oxides of the refractory metalis added comprises aluminum or a heavier metal as the major constituent,the molten salt solvent will usually float on top of the metallic phasemuch in the manner of a conventional salt cover. While the inventionwill be illustrated largely by examples referring to such floatingmolten salt solvents, it will be well understood by those versed in theart that it is entirely within the scope of the invention to employmolten salt solvents of a specific gravity such that they will largelyor entirely drop to a position below the molten metal in the melting andreaction vessel.

We have also found that the percentage of refractory metal recovered inthe alloy obtained by the process of the invention from refractory metaloxide or oxides varies within certain limits as a function of the excessof molten salt solvent overthe secondary oxide formed by the process.The relationship is not a linear one. With a very small excess of moltensalt solvent over the secondary oxide formed, the improvement in yieldof refractory metal is noticeable, but not economically significant.Beyond a certain excess of molten salt solvent, on the other hand, therecovery of refractory metal in alloy form improves at such aninsignificant rate, that the additional expense for additional saltsolvent and its handling is no longer warranted. Generally, we prefer,therefore, to use an amount of molten salt solvent the Weight of whichis about 2.2 to eight times the weight of the secondary oxide formed inthe process of the invention by the oxidation of the reducing metal to anon-metallic slag.

As previously mentioned, the preferred reducing metals for the processof this invention are aluminum and magnesium because of the high heat offormation of their oxides at the preferred reaction temperatures,because of their low cost and ready availability, and, further, becauseof the relative simplicity of operation which they permit. The preferredmolten salt solvents for the process of the invention thuscomprise'molten salts or mixtures of salts which readily dissolvealuminum oxide or magnesium oxide at the preferred reaction temperature.Molten cryolite is of special advantage where aluminum is employed asthe reducing agent. Although the initial cost of cryolite is relativelyhigh, it may be recovered and reused almost indefinitely. A moltencryolite solvent may be readily separated from the molten alloy formedin the process of the invention and may be subjected to electrolysis bythe well known method employed in the recovery of aluminum from bauxitewhich yields cryolite substantially depleted of alumina and ready to bereturned to the process of the invention, and metallic aluminum whichmay also be returned to the reduction process of the invention. i

As previously mentioned, fluorides other than cryolite, chlorides andmixtures of fluorides and chlorides of metals of the first through thethird groups of the periodic system are suitable for performing theprocess of the invention in a temperature range of 800 to 1600 C. Theymust be selected so as to show high dissolving power for the secondaryoxide formed while only sparingly dissolving the primary oxide of therefractory metal which is to be produced. Molten cryolite dissolves upto 18% of its weight of alumina while still maintaining the freefluidity required for ready separation of the molten salt solvent withthe secondary oxide dissolved therein from the alloy formed. Cryolite,on the other hand, does not readily dissolve refractory metal oxidessuch as titanium dioxide.

It will be appreciated that use of a substantial excess of molten saltsolvent in the process of the invention has a function entirelydifferent from that of a small amount of oxide-dissolving fluxescustomarily used in melting operations. Such fluxes are adequate only todissolve. films of oxide formed on the metal surface by oxidation withatmospheric oxygen or the like and to permit coalescence of individualmetal particles into a homogeneous metal body. The fluxes commonlyemployed are useful in melting a metal or alloy already produced inanother operation, they would, however, be of no assistance in a primarysmelting process such as the process of the invention in which a metalis to be prepared from its oxide, and the slag formed by oxidation ofthe reducing agent must be removed. The basic difference between thefunction of commonly known fluxes and the non-metallic solvent melt ofour invention is thus emphasized and should be borne in mind so as tofacilitate the understanding of the inventive process. It should also benoted that the relatively large amount of molten salt solvent present inthe reaction mixtures acts as an acceptor of thermal energy, thusfurther serving as a reaction moderator. The inventive process isperformed at a temperature intermediate the melting point of themetallic constituents present before the reaction and the melting pointof the refractory metal or metals the oxide or oxides of which are beingreduced. It is one of the principal advantages of the invention that thereduction of the oxides of the refractory metals may be performed at atemperature substantially below the melting point of the refractorymetals proper and, therefore, at a temperature much lower than that"required in processes in which a refractory metal in the metallic stateis alloyed with other constituents. The maximum temperature reached inthe inventive process is much lower than that of the aluminothermicprocesses of the prior art. The use of the molten salt solvent of theinvention has been found to give superior yields of refractory metal atlower temperatures than are obtainable under otherwise similarconditions, but without molten salt solvents and at the higher temperatures required for this reason. t r

The process of the invention is preferably carried out in an electricfurnace having an inert atmosphere, but furnaces heated in any othermanner may be used as Well as will be obvious to those skilled in theart.

It will be realized that the inventive process is very economical sincethe refractory metal constituents, which usually determine the cost, aresupplied in the form of their oxides which are much less expensive andare generally more readily available than refractory metals in theirmetallic state.

The inventive process is particularly advantageous for the production ofso-called master alloys, that is of alloys containing a relatively highpercentage, for example 540%, of a refractory metal. The melting pointof such a master alloy is somewhat higher than that of thenon-refractory base alloy or metal, but well below that of therefractory metal proper. In order to produce an alloy of relatively lowrefractory metal content from such a master alloy, the alloy or metalbase need to be melted and heated only to the melting point of themaster alloy, whereupon a predetermined amount of master alloy is added.The refractory metal content of the master alloy is thus diluted by themolten base alloy or metal whereby a refractory metal alloy of lowerrefractory metal content than that of the master alloy is obtained.Sinceas previously set forththe melting point of the master alloy isbelow that of the refractory metal proper, it will be realized that thedrawbacks of conventional processes are substantially eliminated by theprocess of the invention.

The reducing metals of this invention may be employed in powder, ingotor shredded form.

The invention will now be described by several examples but it should beunderstood that the examples are given by way of illustration ratherthan by way of limitation and that many changes may be made hereinwithout departing in any way from the scope and spirit of the invention.

Example 1 75 grams of aluminum are melted by an electric arc in amagnesia crucible under an atmosphere of argon gas.

48 grams of iron oxide F6 0 59.5 grams of manganese oxide (Mn O and 62.3grams of titanium dioxide (TiO are pulverized and mixed intimately. Themixture is added to the molten metal with stirring and 300 grams of amolten mixture of 98% cryolite and 2% zinc chloride is added. Thereaction between the molten aluminum and the metal oxides is initiatedby the electric arc. ture of the mixture to 1600 C. When the reactionsubsides, this temperature is maintained by the electric arc.

Aluminum oxide is formed by the reaction of the aluminum with the metaloxides and dissolves in'the molten mixture of non-metallic compounds.This molten mixture forms a layer which floats on top of the alloyformed and is easily separated therefrom. The alloy formed weighs 99grams and contains:

7 Percent Titanium 19 Aluminum 21 Manganese 33 Iron 24 Insoluble BalanceThis alloy may advantageously be used as a master alloy in theproduction of low-titanium steel.

Example 2 The heat of reaction gradually raises the temperapoint ofabout 800 C., 22.5 grams of TiO powder are then added.

Two distinct layers are formed after the reaction of the aluminumwith'the titanium dioxide, that is a molten aluminum-titanium layer, anda molten salt solvent layer containing the aluminum oxide formed by thereaction of the aluminum with the titanium oxide. The crucible ispermitted to cool to about 1000 C. and the solvent layer which is stillquite fluid is poured off.

156 grams of a master alloy of the following composition are obtained:

Percent Titanium 4.6 Aluminum 93.8 Insoluble Balance Example 3 'PercentTitanium 25.05 Aluminum 67.73 Insoluble Balance Example 4 388 grams ofingot aluminum are melted in a magnesia crucible by induction heatingand the temperature of the melt is raised to approximately 1000 C.

A powdered mixture of 175 grams of titanium dioxide and 600 grams ofcryolite is added gradually in several small batches,-while an argonatmosphere is maintained over the melt. The reaction of the moltenaluminum and of the titanium dioxide is initiated instantly by the heatof the molten metal. After the last addition has been made, heating iscontinued until the temperature of the melt reaches 1310 C. and issufliciently high for pouring. The melt is poured into a steel mold andcooled.

Metal and non-metallic solvent phase separate in the mold and 395 gramsof alloy of the following composition are obtained:

Example 5 In order to determine the influence of the excess of moltensalt solvent on the yield of refractory metal, a v

series of aluminum-titanium master alloys was prepared by the method ofExample .4 with the following results:

Composition of Titanium Starting Batch Alumina Recovered in Formed RatioAlloy Batch Theoret- Alumina N o. ically, to

Alumi- T102, Cryo- Grams Cryolite I num, Grams lite, Grams Percent GramsGrams The results of the six experiments have been plotted o'n'theaccompanying graph which illustrates the rela,

tionship of the ratio of alumina to cryolite to the per- ,centageoftitanium recovered inthe final alloy. From the curve, obtained itwill'be readily seen that the yield of titanium. is rather. poor (lessthan 40%) when the ratio of alumina to cryolite is below 1:2. When thiscrucible by induction heating.

ratio is increased to above 12.2, the yield ofititanium Example 200grams of cryolite are intimately mixed with 100 grams of sodiumchloride,5O grams of titanium dioxide, and 10 grams of calcium chloride.A block of 135 grams of magnesium metal is placed in a magnesia Icrucible and the prepared mixture is packed around the Example 9., 584grams of ingot aluminum are melted in a zirconia A mixture of 96.1 gramsof zirconiurn'oxide and 271 grams of cryolite is added to the moltenaluminum at a temperatureof about 980 C. under an argon atmosphere.

The reaction between the'molten aluminum and the zirconium oxide isinitiated spontaneously under the prevailing conditions. After thereaction subsides, the melt is heated to 1185 C'. to make itsufliciently fluid. is then poured into a pre-heated steel mold in whichthe A non-metallic solvent phase solidifies separately from the block.The magnesia crucible is placed inside a graphite crucible and mountedin the coil of an induction furnace. The charge is heated under an argonatmosphere until melted and is then allowed to cool. several smallbuttons at thetop of the fused non-metallic phase. The buttons areremelted with a mixture of 85 grams of sodium chloride and 15 grams ofcalcium fluoride to form a single button of 65 grams containing PercentTitanium I 5.6 Magnesium 93.2

Insoluble Balance Example 7 789 grams of ingot aluminum are melted in amagnesia crucible by induction heating. An intimate mixture Metalseparates in i cryolite were.mixed intimately and are added in several.7

metal alloy. The alloy obtained weighs 562 lowing composition:

grams and has the fol- Percent Zirconium 6.43'

Aluminum 92.3

Insoluble Balance Example 10 I -376 grams of ingot aluminum are meltedin a magnesia crucible by induction heating.

69.1 grams of boron oxide (B 0 and 495 gramsof small portions to themolten aluminum under an argon 7 atmosphere at a temperature ofapproximately 970 C.

of 144 grams of molybdenum trioxide and 560 grams of cryolite is thengradually added to the molten aluminum under an argon atmosphere atsucha rate as tokee the temperature of the melt above 1000 C. 0

The reaction of the molten aluminum with the molybdenum trioxide isinitiated instantly by the heat of'the melt. After the last addition ofmolybdenum oxide, the melt is heated until its temperature reaches 1180C. and is sufficiently high for pouring. The melt is then poured into apreheated steel moldiand permitted to solidify. Metal and non-metallicphase separate in the 'mold. 'The alloy obtained weighed 704 grams andhad the following composition:

Percent Molybdenum 8.94. Aluminum 89.6

Insoluble Balance Example 8 454 grams of ingot aluminum are heated tothe melting point in a magnesia crucible by induction heating.

A powdered mixture of 109.2 grams of vanadium pentoxide and 510 grams ofcryolite is added under an argon atmosphere in several small batches tomaintain the temperature of the melt substantially at 1000 C. Thereaction between the aluminum and the vanadium pentoxide is initiatedspontaneously by the heat of the molten metal. After the last additionhas been made and the reaction subsides, the reaction mixture is heatedto approximately 1200 C. when it is fluid enough to be poured into apre-heated steel mold where it is allowed to cool. Metal andnon-metallic phase separate in the mold.

1 395 grams of an alloy having the following composition are obtained:

Percent Vanadium 10.1 Aluminum p 88. 1

' of the molten metal.

The reaction between the aluminum and the boron'oxide is initiatedspontaneously at this temperature by the heat After the reactionsubsides, the reaction mixture is heated 'until the temperature reaches1120 C. and the melt is fluid enough for pouring into? a preheated steelmold. The alloy, separated from the non-metallic phase aftersolidification, has the following composition: I

Percent BOIOn 4.?)

Aluminum 93.8

Insoluble -1 Balance by induction heating. 138 grams of aluminum arethen added to the molten copper.

An intimate powdered mixture of 209 grams of manganese dioxide and 590grams of cryolite is prepared and is added under an argon cover inseveral small portions.

to the molten base alloy. The reaction between the aluminum and themanganese dioxide is initiated spun;

taneously by the heat of the molten metal. After the reaction subsides,the contents of the crucible are heated until the temperature of thesupernatant non-metallic melt is 1100" C. and the melt is ready forpouring. It,

is then poured into a pre-heated steel mold. The alloy separated fromthe non-metallic phase weighs 421 grams and has the followingcomposition:

, Percent Manganese 7.9 Aluminum 3.1 88.95

Copper Example 12 617 of copper are melted in a ziuconia cruciblebyinduction heating and 51 grams of aluminum metal are dissolved in themolten copper.

A powdered mixture of 122 grams of titanium dioxide and 500 grams ofcryolite is added under an argon atmosphere. The reaction between thealuminum and the titaniumoxide starts spontaneously at the melting pointof the copper-aluminum alloy. After the reaction subsides, heating isresumed to make the alloy fluid enough for pouring. The melt is thenpoured into a preheated steel mold-and allowed to cool.

630 grams of an alloy of the following composition are obtained:

' Percent Titanium 7.6 Copper 85.05 Aluminum 3.6

Insoluble Balance As'can be seen from Examples 1 to 12, 60 to 85% of Ithe refractory metals introduced in oxide form into the process of theinvention are recovered in the alloys.

Resuits were particularly favorable in the alloys of titanium .andaluminum which show a titanium recovery of 72 to 90% of the titaniumadded in the oxide form. The common metals added were recovered in thealloys at yields varying between 90 and 95%.

Even better recovery of the refractory metals and greater heat economycan be achieved by continuous operation Of the process of the inventionas illustrated in the following example:

Example 13 715 grams of ingot aluminum are melted in a crucible byinduction heating. The crucible is provided with two taps, one beinglocated near the bottom, the other one 1 about one third of the heightbelow the top of the crucible.

165 grams of titanium dioxide are carefully mixed With 86 grams ofaluminum powder and 904 grams of cryolite. The mixture is added under anargon atmosphere to the molten aluminum in small batches. Ex-

I, ternal heat is applied as needed if the reaction becomes 7 toosluggish.

The reaction between the aluminum and the titanium dioxide is initiatedspontaneously. After approximately one half of the cryolite-titaniumdioxide mixture is added,

the reaction is permitted to subside, the contents of the crucible areheated to 1070 C. and the greater part of the supernatant non-metallicmelt is drawn oif through I the upper tap.

Percent Titanium 12.98 Aluminum 84.3

Insoluble Balance The collected non-metallic phase has the followingcomposition:

Percent Aluminum oxide 13.9 Titanium dioxide 1.1 Cryolite 85.0

It is thus essentially a solution of alumina in cryolite.

The non-metallic melt is fed to an electrolytic cell having a carbonanode and .walls covered with a carbon lining which serves as cathode.The solution is kept at a temperature of 950 C. by thepassage ofelectric current and electrolyzed in a well-known manner. A voltage ofvolts applied to the electrodes of the cells produces a current densityof 1,000 amps. per sq. ft. at the anode. Aluminum metal in the moltenstate collects at the bottom of the cell and is drawn off from there tobe returned to the melting crucible of the reduction process. Thecryolite depleted of alumina is drawn from the top of the cell and isready to be reused in the process of the invention.

While a continuous batch process was described in the above example, theprocess can readily be made fully continuous by adding to the reactionvessel a mixture of aluminum and titanium oxide in'a ratiosubstantially'corresponding to the composition of the alloy which is tobe prepared, and containing the necessary small amounts of cryoliterequired to compensate for losses which mainly occur by evaporation. Thecryolite melt is circulated between the reaction vessel, in which thereaction between the aluminum and the titanium dioxide is performed andthe electrolytic cell in which the alumina is removed. We have foundthat the titanium dioxide does not accumulate in the non-metallicphase-but reaches a maximum equilibrium value'substantially at 1.1%corresponding to the solubility of TiO in cryolite at approximatelylOOO"C.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not limitedthereto, but 'is to be construed broadly and restricted solely by thescope of the appended claims.

What is claimed is: 1. A one-step process for the preparation'of analloy, which comprises reacting an oxide of at least one refractorymetal with an equivalent amount of reducing metal above the meltingpoint of said reducing metal, whereby said refractory metal oxide isreduced to the metallic state and a slag-forming oxide of said reducingmetal is formed, said reaction being carried out in the presence of anamount of molten, non-reacting metal capable of alloying with saidrefractory metal and in the presence of a molten salt solvent capable ofdissolving the slag-comprising reducing metal oxide formed during thereaction, said reducing metal having a lower position in theelectromotive series at the reaction temperature than said refractorymetal, and said molten salt solvent being present in an excesssuflicient to'dissolve said slag formed by said reducing metal oxide.

2. In a process as claimed in claim 1 wherein said refractory metal hasa melting point of above 1700 C.

'3. In a process as claimed in claim L' herein said refractory metaloxide is an oxide of a refractory metal selected from the groupconsisting of titanium, 'zirconium, molybdenum, vanadium, boron,chromium and manganese.

4. In a process as claimed in claim 1, wherein said reducing metal isselected from the group consisting of aluminum and magnesium.-

5. In a process as claimed in claim 1, wherein said non-reacting metaland said reducing metal are identical metals.

6. In a process as claimed in claim 1, wherein said non-reacting metalis copper.

7. In a process as claimed in claim 1, wherein said molten salt solventis selected from the group consisting of metal chlorides, metalfluorides and mixtures of metal chlorides and metal fluorides having aboiling point above about 700 C. and wherein the metal constituentthereof belongs to the first through third groups of the periodicsystem.

8. In a process as claimed in claim 1, wherein said molten salt solventcomprises cryolite.

9. In a process as claimed in claim 1, wherein said molten salt solventcomprises sodium chloride and calcium fluoride.

10. In a process as claimed in claim 1, wherein said molten salt solventcomprises cryolite and zinc chloride.

11. In a process as claimed in claim 1, wherein the ratio betweenreducing metal oxide slag formed by the reaction and molten salt solventis between about 1:2.2 and 1:8.0.

12. In a process as claimed in claim 1, wherein the l with an additionalequivalent amount of reducing metal to be reduced to the metallic state.

14. In a process as claimed in claim 1, wherein said molten salt solventand said reducing metal oxide slag dissolved in said solvent areseparated from the metal constituents, whereafter the solvent melt thusobtained is electrolysed to recover reducing metal and salt solvent forrecycling.

15. A one-step process for the preparation of an alloy, which comprisesreacting in a reaction zone an oxide of at least one metal selected fromthe group consisting of titanium, zirconium, molybdenum, vanadium,chromium, manganese and boron with an equivalent amount of a reducingmetal selected from the group consisting of aluminum and magnesium abovethe melting point of said reducing metal, whereby said metal oxide isreduced to the metallic state and a slag-forming oxide of said reducingmetal is formed, said reaction being carried out in the presence of anamount of a molten, non-reacting metal capable of alloying with saidrefractory metal and in the presence of ,a molten salt solvent capableof dissolving the reducing metal oxide slag formed during the reaction,the ratio between said molten salt solvent and said reducing metal oxideslag being between about 22:1 and 8:1 and said molten salt solvent beingselected from the group consisting of metal chlorides, metal fluoridesand mixtures of metal chlorides and metal fluorides having a boilingpoint above about 700 C. wherein the metal constituent of said saltsolvent belongs to the first through third groups ofthe periodic system,whereby a molten alloy layer and a 18. In a process as claimed in claim15, wherein portions of said alloy layer and said second layer aresubstantially continuously withdrawn and fresh amounts of saidrefractory metal oxide, equivalent amounts of said reducing metal, saidnon-reacting metal and said molten salt solvent are supplied inpredetermined amounts to said reaction zone, whereby fresh amounts ofalloy layer and second layer are continuously formed.

19. A one-step process for the continuous preparation of an alloy, whichcomprises reacting in a reaction zone an oxide of at least onerefractory metal with an equivalent amount of aluminum above the meltingpoint of aluminum, whereby refractory metal and aluminum oxide areformed, said process being carried out in the presence of an amount ofmolten, non-reacting metal capable of alloying with said refractorymetal and in the presence of cryolite, the ratio of cryolite to aluminumoxide formed being between about 2.2:1 and 8.0:1, whereby an upper layercomprising cryolite and aluminum oxide dissolved therein and a loweralloy layer are obtained, continuously drawing oif from said reactionzone said alloy layer and said upper layer, and continuously supplyingfresh amounts of refractory metal oxide, aluminum, non-reacting metaland cryolite to said reaction zone.

20. In a process as claimed in claim 19, wherein said upper layer iselectrolyzed for separating the aluminum and the cryolite from eachother, and recycling said aluminum and said cryolite to said reactionzone.

References Cited in the file of this patent UNITED STATES PATENTS1,020,517' Rossi Mar. 19, 1912 1,089,773 Kraus Mar. 10, 1914 1,533,505Lubowsky Apr. 14, 1925 1,562,041 Pacz Nov. 17, 1925 1,602,542 MardenOct. 12, 1926 1,912,382 Nock June 6, 1933 2,013,877 Comstock Sept. 10,1935 2,550,447 Blumenthal Apr. 24, 1951 2,578,098 Southard Dec. 11, 19512,781,261 Kamlet Feb. 12, 1957

1. A ONE-STEP PROCESS FOR THE PREPARATION OF AN ALLOY, WHICH COMPRISESREACTING AN OXIDE OF AT LEAST ONE REFRACTORY METAL WITH AN EQUIVALENTAMOUNT OF REDUCING METAL ABOVE THE MELTING POINT OF SAID REDUCING METAL,WHEREBY SAID REFACTORY METAL OXIDE IS REDUCED TO THE METALLIC STATE ANDA SLAG-FORMING OXIDE IS REDUCED TO THE METAL IS FORMED, SAID REACTIONBEING CARRIED OUT IN THE PRESENCE OF AN AMOUNT OF MOLTEN NON-REACTINGMETAL CAPABLE OF ALLOYING WITH SAID REFRACTORY METAL AND IN THE PRESENCEOF A MOLTEN SALT SOLVENT CAPABLE OF DISSOLVING THE SLAG-COMPRISINGREDUCING METAL OXIDE FORMED DURING THE REACTION, SAID REDUCING METALHAVING A LOWER POSITION IN THE ELECTROMOTIVE SERIES AT THE REACTIONTEMPERATURE THAN SAID REFRACTORY METAL, AND SAID MOLTEN SALT SOLVENTBEING PRESENT IN AN EXCESS SUFFICIENT TO DISSOLVE SAID SLAG FORMED BYSAID REDUCING METAL OXIDE.